The present disclosure relates to covers, referred to as tarping systems, for open-topped containers. The invention is particularly related to a tarping system for use with hauling vehicles, such as dump trucks, in which the flexible cover or tarpaulin extends across the open top of the truck container.
Some hauling vehicles, such as dump trucks, include open-topped containers used for hauling or storing various materials. For example, in a typical dump truck application, the container may be used to haul earth, gravel, aggregate, or other products. In addition, the container may be used to haul organic materials, such as grain or produce.
Depending upon the nature of the hauled materials, users may desire to provide a cover for the container. Rigid covers, which may be hinged from one end of the container body, are well known; however, rigid covers have gradually given way in the industry to flexible tarping systems. Flexible tarping systems can be easily stowed when a cover is not necessary, such as when the container is being loaded and unloaded. Moreover, flexible tarping systems are much easier to deploy than rigid covers.
A variety of flexible tarping systems have been developed that utilize tarpaulins (“tarps”). One such tarping system includes a tarp that is wound around a spool at one end of the container. A rope attached to the free end of the tarp can be used to unwind or deploy the tarp manually over the length of the container. Manual deployment types of flexible tarping systems are more easily deployed than rigid covers; however, some flexible tarping systems can be even more conveniently deployed.
As illustrated in FIG. 1, some known flexible tarping systems include a spring biased U-shaped bail arm 10 that automatically covers the open top of the container. The U-shaped bail arm 10 is pivotally mounted at its ends to the base of a container 14. The horizontal crossbar of the U-shaped bail arm 10 is attached to the first end of a tarp 18. The second end of the tarp 18 is wound upon a tarp roller 22 at the front of the container 14. An extension mechanism 26, such as a pair of springs, biases the bail arm 10 toward the rear of the container 14. A release member (not illustrated) maintains the position of the bail arm 10 toward the front of the container 14, against the force of the extension mechanism 26. To cover the container 14 the release member is disengaged causing the extension mechanism 26 to pivot the bail arm 10 toward the rear of the container 14. The rearward movement of the bail arm 10 unfurls the tarp 18 from tarp roller 22 and covers the container 14. A hand crank or motor 30 can be coupled to the tarp roller 22 to rewind the tarp 18 and pivot the bail arm 10 toward the front of the container 14 in order to uncover the container 14. As illustrated, the motor 30 is usually mounted on the top front portion of the container 14, close to the tarp roller 22.
While the above described tarping system covers and uncovers an open-topped container 14 sufficiently well, there is always room for improvement. For example, in some flexible tarping systems the springs forming the extension mechanism 26 may not always hold the horizontal crossbar of the bail arm 10 against the rear portion of the container 14, resulting in a tarping system that may improperly seal the container 14 or that bounces as the container 14 is moved. In particular, the problem becomes compounded when the container 14 is attached to a truck that is traveling at highway speed, because there is a tendency for wind to cause billowing and flapping of the tarp 18. An extension mechanism 26 having springs that are sufficiently strong could be utilized to hold the tarp 18 firmly against the container 14; however, when strong springs are utilized it becomes prohibitively difficult to wind the crank when retracting the tarp 18. Automating the retraction process with a motor 30 reduces the physical effort required to retract the tarp 18, but the position of the automation system, specifically the motor 30, often leads to additional shortcomings, as explained below.
Automated flexible tarping systems often include a motor 30 positioned near the tarp roller 22 at the front of the container 14. Positioning the motor 30 near the front of the container 14 places the motor 30 in position susceptible to damage, because the upper front portion of many containers 14 is an area prone to damage. For example, when a container 14 is the pivotal open-topped container 14 of a dump truck, the front wall of the container 14 might be forced into contact with tree limbs or other structures, which could damage the motor 30. Furthermore, the top portion of the container 14, including the motor 30, may become inadvertently damaged due to contact from backhoe buckets and other types of construction vehicles, as evidenced by the replaceable wooden sideboards on many dump truck containers 14. Accordingly, positioning the motor 30 of an automated flexible tarping system on the upper front portion of a dump truck container 14 increases the likelihood that the retraction mechanism may become damaged as the truck is operated.